Melanocytic Cells Research Articles

Conjunctival tumour as an acute myeloblastic lymphoma presentation in a paediatric patient

AbstractPurpose: The most frequent ocular tumours are those that affect the conjunctiva which have a wide spectrum of presentation and can arise from any cell lineage that forms the conjunctiva, being the most representatives those that origins from epithelial and melanocytic cells. A case of a 10‐month‐old female patient who was diagnosed with acute myeloblastic leukaemia after studying a conjunctival tumour is presented.Methods: The case of a 10‐month‐old female with a conjunctival lesion located in the right eye who was also being studied for two masses, one on the right preauricular zone and the other on the left zygomatic area is described. About her medical history, she had an aplastic crisis due to parvovirus infection when she was 8 months old. No ophthalmological background was reported. On the clinical exam of the right eye, a pink conjunctival lesion located in the outer corner of the superior conjunctival fornix was found. The ocular motility was normal and the eyeball position was normal.Results: A biopsy of the conjunctival mass was performed immediately. The histopathology report showed infiltration with leukaemic cells. After this finding, a bone marrow biopsy, lumbar puncture, full‐body CT scan and an orbit MRI were performed, concluding the patient was suffering from an acute myeloblastic leukaemia with extramedullary involvement (face, orbit, ovaries) and central nervous system affection. After two cycles of chemotherapy, complete remission is achieved, including the conjunctival and orbital lesions.Conclusions: Haematology‐Oncology systemic diseases can imply the eye and the orbit. The manifestations most commonly found in children with leukaemia are proptosis, retinal and choroidal affection, optic nerve damage, and sixth nerve palsy. In the conjunctiva, it usually manifests as a subconjunctival salmon‐pink flesh coloured mass. Excision‐biopsy study is essential in the differential diagnosis of conjunctival neoplasms.

Morphological evaluation of melanocytic lesions with three-dimensional line-field confocal optical coherence tomography: correlation with histopathology and reflectance confocal microscopy. A pilot study.

Line-field confocal optical coherence tomography (LC-OCT) is a new invivo emerging technique that provides cellular resolution, allows deep imaging (400 μm) and produces real-time images in both the horizontal and vertical plane and in three dimensions. No previous description of different subtypes of melanocytic lesions and their correlation with histopathology and reflectance confocal microscopy has been reported. To describe the features of melanocytic lesions by LC-OCT and their correlation with histopathology and reflectance confocal microscopy (RCM) findings. Selected melanocytic benign lesions and melanomas were imaged invivo with RCM and LC-OCT at the Fundación Hospital Clinic (Barcelona, Spain). A minimum area of 4 × 4 mm (block image) at four depths (stratum granulosum, suprabasal, layer dermoepidermal junction and upper dermis) were acquired with RCM and a minimum of three cubes with LC-OCT. Horizontal, vertical sections and three-dimensional (3D) cubes of LC-OCT were matched with RCM (Vivablock two-dimensional composite mosaic) and histopathology, with ~5 μm lateral resolution accuracy (the same cell nuclei were measured in X, Y and Z) and evaluated by three observers experienced in using RCM and histopathology. In total, 12 melanocytic tumours (2 insitu melanomas, 2 invasive melanomas, 4 atypical naevi, 2 intradermal naevi, 1 compound naevus and 1 junctional naevus) were included. High correlation with 5 μm accuracy between RCM and LC-OCT was observed for each tumour. The 3D images of melanocytic lesions were obtained with cellular resolution and correlated with both RCM and histopathology, allowing an understanding of the architecture and precise correlation at the cellular level with RCM. Similarities between LC-OCT and RCM for the described diagnostic features and architecture (nests of melanocytic cells, ringed and meshwork pattern, and cellular details of tumour cells as dendritic and pagetoid cells) were confirmed. The main advantage of diagnosis by RCM fixed probe was the ability to produce larger scans of the lesion using mosaicing compared with an LC-OCT handheld probe. LC-OCT allows the architectural and cellular description of different types of melanocytic lesions. LC-OCT showed high correlation with histopathology (vertical sections) and RCM (horizontal sections) in melanocytic lesions. Diagnostic criteria for RCM were similar to those for LC-OCT.

A multi-stage melanoma recognition framework with deep residual neural network and hyperparameter optimization-based decision support in dermoscopy images

This paper developed a novel melanoma diagnosis model from dermoscopy images using a novel hybrid model. Melanoma is the most dangerous and rarest type of skin cancer. It is seen because of the uncontrolled proliferation of melanocyte cells that give color to the skin. Dermoscopy is a critical auxiliary diagnostic method in the differentiation of pigmented moles, which show moles by magnifying 10–20 times from skin cancers. This paper proposes a multi-stage melanoma recognition framework withskin lesion images obtained from dermoscopy. This model developed a practical pre-processing approach that includes dilation andpooling layers to remove hair details and reveal details in dermoscopy images. A deep residual neural network was then utilized as the feature extractor for processed images.Additionally, the Relief algorithm selected practical and distinctive features from these features. Finally, these selected features were fed to the input of the support vector machine (SVM) classifier. In addition, the Bayesian optimization algorithm was used for the optimum parameter selection of the SVM method. The International Skin Imaging Collaboration (ISIC-2019 and ISIC-2020) datasets were used to test the performance of the proposed model. As a result, the proposed model produced approximately 99% accuracy forclassifying melanoma or benign from skin lesion images. These results show that the proposed model can help physicians to automatically identify melanoma based on dermatological imaging.

Massively parallel reporter assays and variant scoring identified functional variants and target genes for melanoma loci and highlighted cell-type specificity

The most recent genome-wide association study (GWAS) of cutaneous melanoma identified 54 risk-associated loci, but functional variants and their target genes for most have not been established. Here, we performed massively parallel reporter assays (MPRAs) by using malignant melanoma and normal melanocyte cells and further integrated multi-layer annotation to systematically prioritize functional variants and susceptibility genes from these GWAS loci. Of 1,992 risk-associated variants tested in MPRAs, we identified 285 from 42 loci (78% of the known loci) displaying significant allelic transcriptional activities in either cell type (FDR<1%). We further characterized MPRA-significant variants by motif prediction, epigenomic annotation, and statistical/functional fine-mapping to create integrative variant scores, which prioritized one to six plausible candidate variants per locus for the 42 loci and nominated a single variant for 43% of these loci. Overlaying the MPRA-significant variants with genome-wide significant expression or methylation quantitative trait loci (eQTLs or meQTLs, respectively) from melanocytes or melanomas identified candidate susceptibility genes for 60% of variants (172 of 285 variants). CRISPRi of top-scoring variants validated their cis-regulatory effect on the eQTL target genes, MAFF (22q13.1) and GPRC5A (12p13.1). Finally, we identified 36 melanoma-specific and 45 melanocyte-specific MPRA-significant variants, a subset of which are linked to cell-type-specific target genes. Analyses of transcription factor availability in MPRA datasets and variant-transcription-factor interaction in eQTL datasets highlighted the roles of transcription factors in cell-type-specific variant functionality. In conclusion, MPRAs along with variant scoring effectively prioritized plausible candidates for most melanoma GWAS loci and highlighted cellular contexts where the susceptibility variants are functional.

A Review on Transfer Learning Approaches for Skin Melanoma Classification

Skin is important organ of our body which covers muscles, bones, and other parts of body. Melanoma is a kind of skin cancer that begins in melanocytes cell. It can influence on the skin only, or it may expand to the bones and organs. It is less common, but more serious and aggressive than other types of skin cancer. Majority of deaths related to skin cancer occur due to Melanoma over the world. For effective treatment it is very important to melanoma identified earlier as possible. As well as detection of the stages of melanoma to recognize depth of spreading of melanocyte cell in other organ of body. Process of Detection of Skin cancer is difficult, expensive, and time-consuming process. Purpose of this research review is to more accurate recognition the types of Melanomas and decrease ratio of false diagnosis using transfer learning model for melanoma classification using AlexNet, VggNet and ResNet. The working of the different transfer learning model, its pros. and cons. Are discuss in this paper.

488 Effect of UVB irradiation in epidermal melanocyte and melanoma cell differentiation and apoptosis

Melanoma is a very heterogeneous neoplasm, with poor chemotherapeutic response. Despite treatment advances, better definition of early molecular steps underlying melanomagenesis is needed. Multiple distinct subpopulations of melanocytes may exist in epidermis, which could explain cutaneous melanoma heterogeneity. Here we assess differentiation and apoptosis status of primary melanocytes (HEM) and melanoma cells (FM3, FM55P, FM55M, SK-MEL-23), after in vitro challenge with UVB irradiation (300 mJ/cm2) for 48h.

Rab32/38-Dependent and -Independent Transport of Tyrosinase to Melanosomes in B16-F1 Melanoma Cells.

B16-F1 melanoma cells have often been used as a model to investigate melanogenesis, but the evidence that melanosome biogenesis and transport occur by the same mechanisms in normal melanocytes and B16-F1 cells is insufficient. In this study, we established knockout B16-F1 cells for each of several key factors in melanogenesis, i.e., tyrosinase (Tyr), Hps4, Rab27A, and Rab32·Rab38 (Rab32/38), and then compared their phenotypes with the phenotypes of corresponding mutant mouse melanocyte cell lines, i.e., melan-c, melan-le, melan-ash, and Rab32-deficient melan-cht cells, respectively. The results showed that Tyr and Rab27A are also indispensable for melanin synthesis and peripheral melanosome distribution, respectively, in B16-F1 cells, but that Hps4 or its downstream targets Rab32/38 are not essential for Tyr transport in B16-F1 cells, suggesting the existence of a Rab32/38-independent Tyr transport mechanism in B16-F1 cells. We then performed comprehensive knockdown screening of Rab small GTPases and identified Rab10 and Rab24, previously uncharacterized Rabs in melanocytes, as being involved in Tyr transport under Rab32/38-null conditions. Our findings indicate a difference between the Tyr transport mechanism in melanocytes and B16-F1 cells in terms of Rab32/38-dependency and a limitation in regard to using melanoma cells as a model for melanocytes, especially when investigating the mechanism of endosomal Tyr transport.

A Novel Furocoumarin Derivative, 5-((diethylamino)me-13 thyl)-3-phenyl-7H-furo [3,2-g] chromen-7-one Upregulates Melanin Synthesis via the Activation of cAMP/PKA and MAPKs Signal Pathway: In Vitro and In Vivo Study.

Psoralen, a major furocoumarin component of the Fructus Psoralen (FP), in combination with ultraviolet radiation, cures abnormal pigmentation disorder. In a previous study, we synthesized a series of linear furocoumarins with different substituents, out of which 5-((diethylamino)methyl)-3-phenyl-7H-furo [3,2-g] chromen-7-one (encoded as 5D3PC) showed better pigmenting effect than others in B16 cells. In this study, we examined the mechanism underlying the melanogenic effect of 5D3PC both in vivo and in vitro. To examine the pigmentation effect, the B16 and human melanocyte cell lines, PIG1 and PIG3V melanocytes were incubated with 5D3PC. In animal experiments, C57BL/6 mice received 5% hydroquinone and were administrated with 5D3PC for 30 days. 5D3PC upregulated the melanin synthesis and tyrosinase in B16 cell, PIG1 and PIG3V. The expression level of tyrosinase (TYR), tyrosinase-related protein-1 (TRP-1) and tyrosinase-related protein-2 (TRP-2), microphthalmia-associated transcription factor (MITF), cyclic adenosine monophosphate (cAMP), phosphorylation of cAMP-responsive element binding protein (p-CREB), phosphorylation of p38 mitogen-activated protein kinase (MAPK), c- phosphorylation of Jun N-terminal kinase (p-JNK) was significantly higher in 5D3PC-treated B16 cells. The oral administration of 5D3PC attenuated the depigmentation of the C57BL/6 vitiligo mice model by increasing the numbers of melanin-containing hair follicles, melanogenic protein, and melanogenesis-relative genes expression in skin tissues.

Protective Effect of the Hydrophilic Extract of Polypodium leucotomos, Fernblock®, against the Synergistic Action of UVA Radiation and Benzo[a]pyrene Pollutant.

Oxidative stress is a harmful effect induced on the skin by polycyclic aromatic hydrocarbons (PAH), including benzo[a]pyrene (BaP) air pollutants. This effect is amplified by the additive damaging effect of the sun, especially through the UVA light component. Besides being one of the main compounds that make up air pollution, BaP can also be found in tar, tobacco smoke, and various foods. In addition to its direct carcinogenic potential, BaP can act as a photosensitizer absorbing sunlight in the UVA range and thus generating ROS and 8-hydroxy-2'-deoxyguanosine (8-OHdG). Fernblock® (FB) is an aqueous extract from the leaves of Polypodium leucotomos that has been proven to exert photoprotective and antioxidant effects on skin cells. In this study, we evaluate the potential of FB to prevent the damage induced by a combination of BaP and UVA light on human keratinocyte and mouse melanocyte cell lines (HaCaT and B16-F10, respectively). In particular, we have analyzed the capacity of FB to counteract the alterations caused on cellular morphology, viability, oxidative stress and melanogenic signaling pathway activation. Our data indicate that FB prevented cell damage and reduced oxidative stress and melanogenic signaling pathway activation caused by a combination of BaP and UVA light irradiation. Altogether, our findings support the fact that FB is able to prevent skin damage caused by the exposure to a combination of UVA and the air pollutant BaP.

Transplantation of autologous epidermal melanocyte-keratinocyte cells suspension for cell therapy of vitiligo: Aclinical evaluation and biometric assessment.

Among several surgical treatments, the use of transplantation of epidermal cultured melanocytes or melanocytes-keratinocytes cell suspension has gained many researchers and dermatologists' attention as a new technique for the treatment of vitiligo. The present study aimed to transplant autologous epidermal melanocytes-keratinocytes cell suspension for the treatment of vitiligo. In this study, 15 volunteer patients aged between 18 and 45 years old were studied. The autologous melanocytes-keratinocytes cell suspension was then transplanted to the region after dermabrasion. The included patients were evaluated by VisioFace, MPA9, and Skin Scanner-DUB once before and 1, 2, and 6months after the transplantation, while the extents of stainability and changes in the transplanted region were recorded. The color contrast between the lesion and normal skin significantly decreased after 1, 2, and 6months of the melanocytes transplantation compared with the pre-procedure (13.8 ± 0.45 before vs. 12.9 ± 0.43, 12.2 ± 0.45, and 10.2 ± 0.34 at months 1, 2, and 6, p < 0.001). Furthermore, melanin index significantly increased six months after cell transplantation compared to the pretreatment (168.3 ± 4.22 vs. 130.5 ± 3.98, p < 0.001). Transplantation of melanocytes cells with dermabrasion can be effective on vitiligo improvement, so it is recommended.

S2179 A Case of Anorectal Junction Melanoma

Introduction: Malignant melanoma of the rectum is an extremely rare disease that is aggressive in nature and often at an advanced stage at the time of diagnosis. We present a case of malignant melanoma of the rectum that was diagnosed on endoscopic polypectomy and staged with endoscopic ultrasound. Case Description/Methods: A 66-year-old, asymptomatic, White female underwent a surveillance colonoscopy. She was noted to have a 20 mm semi-pedunculated rectal polyp (Figure 1), which was piecemeal resected using a hot snare (Figure 1.2). Resection and retrieval were complete. Pathology showed malignant melanoma involving the anal and anorectal junction mucosa (Figure 1.3 and 1.4). The tumor approached the inked resection margin. Immunohistochemical stains were positive for Sox-10 (diffuse and strong) (Figure 1.5), Melan-A (focal), S-100 (focal), and tyrosinase (focal). Stains were negative for pan keratin, CK7, CK20, CDX2, P40, CD56, synaptophysin, CD45, and CEA. EUS performed 3 weeks later showed linear scar just above the dentate line with no residual polyp tissue. Rectal wall at the polypectomy site was thickened without any tumor infiltration and a normal appearing muscular propria. Patient was noted to have 2 hypoechoic lymph nodes 11.4 mm X 8.5 mm and 6.4 mm X 6.0 mm, 8 cm from anal verge (Figure 1.6). Fine needle Aspiration biopsy of the lymph nodes was performed. Pathology from the lymph node showed presence of malignant melanoma. Immunostain positive for MART-1 and SOX-10 but negative for HMB-45. PET/CT did not show any regional or distant metastatic disease. Tumor was staged as Stage III malignant melanoma. Discussion: Malignant melanoma of the distal rectum and anorectal junction is an aggressive and a rare presentation of this disease. It is mostly diagnosed in White women in fifth to sixth decade. Melanocytes are located at the anal transition zone and squamous zone with most anorectal melanomas arising from the dentate line and located at the anal verge or in the anal canal. Due to the hidden location and late onset of symptoms, many of these tumors are advanced by the time of diagnosis. As this case illustrates, tumors are often 20 mm or bigger in size with nodal involvement. Hence the 5 year disease free survival in patients with metastatic disease is only 16%.Figure 1.: 1: Colonoscopy image showing rectal polyp. 2: Colonoscopy image showing post rectal polypectomy site. 3: Pathology showing malignant melanoma involving the anal and anorectal junction mucosa. 4: Pathology showing sheets of melanocytic tumor cells. 5: Pathology showing brown nuclear staining with SOX-10 immunoperoxidase marker. 6: EUS image showing hypoechoic lymph node.

Endogenous DOPA inhibits melanoma through suppression of CHRM1 signaling.

Melanoma risk is 30 times higher in people with lightly pigmented skin versus darkly pigmented skin. Using primary human melanocytes representing the full human skin pigment continuum and preclinical melanoma models, we show that cell-intrinsic differences between dark and light melanocytes regulate melanocyte proliferative capacity and susceptibility to malignant transformation, independent of melanin and ultraviolet exposure. These differences result from dihydroxyphenylalanine (DOPA), a melanin precursor synthesized at higher levels in melanocytes from darkly pigmented skin. We used both high-throughput pharmacologic and genetic in vivo CRISPR screens to determine that DOPA limits melanocyte and melanoma cell proliferation by inhibiting the muscarinic acetylcholine receptor M1 (CHRM1) signaling. Pharmacologic CHRM1 antagonism in melanoma leads to depletion of c-Myc and FOXM1, both of which are proliferation drivers associated with aggressive melanoma. In preclinical mouse melanoma models, pharmacologic inhibition of CHRM1 or FOXM1 inhibited tumor growth. CHRM1 and FOXM1 may be new therapeutic targets for melanoma.

PRIMARY INTRACRANIAL MALIGNANT MELANOMA A RARE PIGMENTED C.N.S LESION : A CASE REPORT AND REVIEW OF LITERATURE

Primary Pigmented lesions of the Central nervous System are rare and diverse group of entities that run the gamut from Benign to malignant[1]. Among Pigmented CNS Tumor, Primary intracranial melanomas possesses a great interest among Neurosurgeons with its varied Clinical and Radiological patterns as they are most often confused and misdiagnosed with Meningioma, Schwannoma and thrombosed aneurysms . Primary cerebral melanomas, derived from the melanocytic cells that are precursor Cells of Melanoblasts considered to be originated from neural crest cells that are normally present in the leptomeninges. They are rare and occur in around 1% of all melanoma cases[2,4]. Primary intracranial malignant melanoma accounts 0.1% of intracranial neoplasms[3]. This report highlights a case of Primary Intracranial malignant melanoma of clivus in 40 year male, who has undergone left Pterional Craniotomy Trans Sylvian approach and excision of Tumor after proper dermatological, ophthalmological and systemic evaluations to exclude presence of any other lesions in the body. Which was proved malignant melanoma via Histopathology. Herein we have reported this case for its rarity and consideration as differential for prompt treatment.

DenseNet-II: an improved deep convolutional neural network for melanoma cancer detection.

Research in the field of medicine and relevant studies evince that melanoma is one of the deadliest cancers. It defines precisely that the condition develops due to uncontrolled growth of melanocytic cells. The current trends in any disease detection revolve around the usage of two main categories of models; these are general machine learning models and deep learning models. Further, the experimental analysis of melanoma has an additional requirement of visual records like dermatological scans or normal camera lens images. This further accentuates the need for a more accurate model for melanoma detection. In this work, we aim to achieve the same, primarily by the extensive usage of neural networks. Our objective is to propose a deep learning CNN framework-based model to improve the accuracy of melanoma detection by customizing the number of layers in the network architecture, activation functions applied, and the dimension of the input array. Models like Resnet, DenseNet, Inception, and VGG have proved to yield appreciable accuracy in melanoma detection. However, in most cases, the dataset was classified into malignant or benign classes only. The dataset used in our research provides seven lesions; these are melanocytic nevi, melanoma, benign keratosis, basal cell carcinoma, actinic keratoses, vascular lesions, and dermatofibroma. Thus, through the HAM10000 dataset and various deep learning models, we diversified the precision factors as well as input qualities. The obtained results are highly propitious and establish its credibility.

Melanocytotoxic chemicals and their toxic mechanisms.

Melanocyte cell death can lead to various melanocyte-related skin diseases including vitiligo and leukoderma. Melanocytotoxic chemicals are one of the most well-known causes of nongenetic melanocyte-related diseases, which induce melanocyte cell death through apoptosis. Various chemicals used in cosmetics, medicine, industry and food additives are known to induce melanocyte cell death, which poses a significant risk to the health of consumers and industrial workers. This review summarizes recently reported melanocytotoxic chemicals and their mechanisms of toxicity in an effort to provide insight into the development of safer chemicals.

Human milk oligosaccharide 2'-fucosyllactose promotes melanin degradation via the autophagic AMPK–ULK1 signaling axis

There is still an unmet need for development of safer antimelanogenic or melanin-degrading agents for skin hyperpigmentation, induced by intrinsic or extrinsic factors including aging or ultraviolet irradiation. Owing to the relatively low cytotoxicity compared with other chemical materials, several studies have explored the role of 2'-fucosyllactose (2'-FL), the most dominant component of human milk oligosaccharides. Here, we showed that 2'-FL reduced melanin levels in both melanocytic cells and a human skin equivalent three-dimensional in vitro model. Regarding the cellular and molecular mechanism, 2'-FL induced LC3I conversion into LC3II, an autophagy activation marker, followed by the formation of LC3II+/PMEL+ autophagosomes. Comparative transcriptome analysis provided a comprehensive understanding for the up- and downstream cellular processes and signaling pathways of the AMPK–ULK1 signaling axis triggered by 2'-FL treatment. Moreover, 2'-FL activated the phosphorylation of AMPK at Thr172 and of ULK1 at Ser555, which were readily reversed in the presence of dorsomorphin, a specific AMPK inhibitor, with consequent reduction of the 2'-FL-mediated hypopigmentation. Taken together, these findings demonstrate that 2'-FL promotes melanin degradation by inducing autophagy through the AMPK–ULK1 axis. Hence, 2'-FL may represent a new natural melanin-degrading agent for hyperpigmentation.

Two novel CreERT2 transgenic mouse lines to study melanocytic cells in vivo.

The skin of adult mammals protects from radiation, physical and chemical insults. While melanocytes and melanocyte-producing stem cells contribute to proper skin function in healthy organisms, dysfunction of these cells can lead to the generation of malignant melanoma-the deadliest type of skin cancer. Addressing cells of the melanocyte lineage in vivo represents a prerequisite for the understanding of melanoma on cellular level and the development of preventive and treatment strategies. Here, the inducible Cre-loxP-system has emerged as a promising tool to specifically target, monitor, and modulate cells in adult mice. Re-analysis of existing sequencing data sets of melanocytic cells revealed that genes with a known function in neural cells, including neural stem cells (Aldh1L1 and Nestin), are also expressed in melanocytic cells. Therefore, in this study, we explored whether the promoter activity of Nestin and Aldh1L1 can serve to target cells of the melanocyte lineage using the inducible CreERT2 -loxP-system. Using an immunohistochemical approach and different time points of analysis, we were able to map the melanocytic fate of recombined stem cells in the adult hair follicle of Nestin-CreERT2 and Aldh1L1-CreERT2 transgenic mice. Thus, we here present two new mouse models and propose their use to study and putatively modulate adult melanocytic cells in vivo.

The molecular mechanisms of vulpinic acid induced programmed cell death in melanoma.

Malignant melanoma is an aggressive skin tumor with a rapidly increasing incidence and there is not yet a successful treatment strategy. Vulpinic acid (VA) is derived from secondary metabolites from lichen species. In the current study, we, for the first time, investigated the anti-cancer effects of VA and the underlying mechanism VA induced programmed cell death in melanoma. The anti-cancer effects of VA on melanoma cells were evaluated by the xCELLigence system, flow cytometry, caspase-3 activity and RT-PCR analysis. Our results showed that VA had a strong anti-proliferative effect on A-375 melanoma cells without damaging human epidermal melanocyte cells. Additionally, VA promoted apoptotic cell death through G2/M arrest and the activation of both intrinsic and extrinsic apoptosis pathways according to the analysis of 88 genes associated with apoptosis by qRT-PCR. Our findings suggest that VA could become an alternative topical and transdermal treatment strategy in the treatment of maligned melanoma cancer. However, further investigations are needed to assess the underlying molecular mechanism of VA mediated apoptotic cell death in the treatment of melanoma.

Analysis of uveal melanomas and paired constitutional DNA for exclusion of a BAP1-tumor predisposition syndrome

Uveal melanoma (UM) is a rare tumor originating from melanocytic cells in the eye. Familial aggregation of UM is rare and can occur as part of the tumor predisposition syndrome BAP1-TPDS. However, family history alone will only identify a subset of patients with BAP1-TPDS. In the present study, we used sequential testing of tumor and blood DNA from UM patients for differential diagnosis of BAP1-TPDS. The study group was an unselected prospective cohort of patients from whom UM tissue was available. First, chromosome 3 status in tumor DNA was determined in all 140 patients who consented to participate. As tumors with disomy 3 rarely show BAP1 alterations, sequence analysis of this gene was performed in the 72 tumors with monosomy 3 (M3) or partial M3 only. We identified oncogenic BAP1 alterations in 52 of these tumors (72%). Targeted sequencing of DNA from matched peripheral blood showed pathogenic variants in two patients (3.8%) thus proving BAP1-TPDS. Only one of these two patients also had a medical history suggestive of this syndrome. Conversely, in three patients known to have had additional tumors before diagnosis of UM, constitutional heterozygosity for a BAP1 mutation was excluded. Altogether, in 50 patients we could exclude BAP1-TPDS with high diagnostic certainty. The results of our study support that genetic testing for BAP1-TPDS should be offered to all patients with UM. Moreover, as genetic information from the tumor can help exclude heritable risk, the strategy for analysis should include efforts to obtain tumor samples for testing.

8-Methoxybutin inhibits α-MSH induced melanogenesis and proliferation of skin melanoma by suppression of the transactivation activity of microphthalmia-associated transcription factor.

Microphthalmia-associated transcription factor (MITF) is highly expressed in melanocytes and is the main regulator of melanogenesis and melanocyte cell fate. Although MITF is important for the differentiation and development of melanocytes, it is also considered an oncogene of skin melanoma. Based on these findings, MITF could be an attractive therapeutic target for skin cancer intervention. This study identified 8-methoxybutin as an inhibitor of MITF and investigated the underlying mechanism. 8-Methoxybutin inhibited α-MSH-induced melanogenesis in murine melanoma cells (B16F10) and skin melanoma proliferation by reducing melanogenic gene expression via blockade of the transactivation activity of MITF. In silico docking analysis and pull-down analysis suggested that 8-methoxybutin binds to the DNA-binding domain of MITF and further inhibits its binding to the E-box in the promoter of target genes, including tyrosinase. In addition, 8-methoxybutin suppressed growth of skin melanoma in a xenograft mouse model. These results indicate that 8-methoxybutin has potential as a therapeutic agent for hyperpigmentation disorder and skin cancer. SIGNIFICANCE STATEMENT: 8-Methoxybutin inhibits MITF transactivation activity resulting suppression of melanogenesis and skin melanoma growth.